Combinations of an organic peroxide and an aromatic tertiary amine have been used since a long time ago, as a polymerization initiator for polymerizing a paste composition containing radically-polymerizable methacrylate or acrylate monomers, oligomers thereof, and prepolymers thereof (for example, see Patent Literature 1). In the combinations, time for polymerization and curing is adjusted, and a preservation stability is given to the paste composition before polymerization, by adjusting the amounts of the organic peroxide and the aromatic tertiary amine to be blended in the paste composition, and using a polymerization inhibitor at the same time.
On the other hand, it is known that oxygen inhibition layers are generated in the composition by polymerization under an oxygen environment (polymerization inhibition), and there are problems, for example the composition has a bad operability as a dental polymerizable composition such as a composite resin for repairing, a resin for constructing tooth foundations, and a resin for producing temporary prostheses, and grinding is difficult to carry out thereto.
As a combination of polymerization initiators, disclosed is a paste type polymerizable composition including a ternary catalyst of a pyrimidinetrione derivative, an organic metal compound, and an organic halogen compound (for example see Patent Literature 2). However, this composition also has a problem of polymerization inhibition.
Further, a dental composition in which hydroperoxide, a thiourea derivative, and a copper compound are combined (for example, see Patent Literature 3), a dental composition including a hydrogen peroxide-polyvinylpyrrolidone complex (for example, see Patent Literature 4), a composition including cumene hydroperoxide and acetylthiourea (for example, see Patent Literature 5), and the like are disclosed. However, even with these dental compositions, the problem of polymerization inhibition has not been solved.
Another disclosure is a redox curing type dental composition including a first agent and a second agent, wherein both the first and second agents contain a polymerizable monomer, and either one of the first and second agents contains an oxidation agent, and the other one of the first and second agents contains a reducing agent, at least one of an aromatic sulfinic acid and a salt thereof, and a ternary aliphatic amine (for example, see Patent Literature 6). However, even with this composition, the problem of polymerization inhibition has not been solved.
As a method for reducing the polymerization inhibition, disclosed is a technique of adding a layered silicate mineral for inhibiting the generation of oxygen inhibition layers (for example, see Patent Literature 7). However, unnecessary addition of mineral has a problem of causing the operability and polymerization property to get worse and causing the strength of the hardened body to degrade.